TechMark Arena 2026 is a transdisciplinary master thesis school where the students work on projects within the scope of DCC research. TechMark Arena 2026 focuses on the topic of Electrification of pulp and wood components.
We asked our students to write about themselves and their research. And here is our first student, Viktor Fogelberg.
The future of compact thermal management?
As we brave the winter here in Stockholm, Sweden, we’re constantly reminded of how important heat (and the lack of it) is for our safety and comfort. One of the ways to keep warm during long days in the snow is to use heating pads. By breaking a small metal disk inside a liquid pouch, it solidifies and releases heat, warming your hands. These heating pads are an example of phase change materials; an interesting class of compounds used for thermal management. Another example is ice; instead of releasing heat by solidifying, it melts and absorbs heat from the environment or, for example, a drink in summer.
By using this interesting group of materials, we can develop new products which can be used to keep a steady temperature. Phase change materials have diverse applications; they can be incorporated into buildings as a thermal buffer, they can be used in rapid access memory for computing, improve the efficiency of solar cells, and be used with batteries to reduce the risk of thermal runaway.
My name is Viktor Fogelberg, and I am currently conducting my master’s thesis in collaboration between the Digital Cellulose Center, RISE and Linköpings Universitet (LiU). The aim of my project is to combine the conventional phase change material paraffin with cellulose paper and graphene to create a flexible and lightweight composite.
Paraffin is an established phase change material with high heat storing capabilities, but it suffers from some considerable drawbacks. When the paraffin absorbs heat, it turns into a liquid which may leak and be released into the environment. To be able to absorb heat quickly, a phase change material needs to have a high thermal conductivity, which paraffin lacks. On top of this, paraffin is derived from petroleum, a non-renewable resource.
In my project, the paraffin is incorporated into paper, which prevents leaking. By adding graphene, thermal pathways are created inside the composite, which improves the low thermal conductivity. While the non-renewability of paraffin is difficult to improve, other phase change materials are possible. One alternative is to use fatty acids, which can be derived from a variety of plant and animal sources.
At the time of writing, I’m evaluating different techniques to encase the paraffin in the paper. One conventional approach is impregnation, letting the paper sheets absorb molten paraffin. Another approach is dispersing paraffin in water and directly incorporating it in the paper making process. This is utilized when creating wax papers used in the food industry. To disperse the non-polar paraffin in water, I’m using nanofibrillated cellulose which has been shown to be excellent at dispersing graphene.
I chose this master’s thesis because of the opportunity to work closely with RISE, DCC and industry partners in creating a material of the future. I’m also excited to use my theoretical skills developed at KTH in practice, working with many interesting analytical techniques at RISE and LiU.
/Viktor Fogelberg